Answer: You may notice that your spa will start turning green with dead algae but your pool will look great. This happens because the spa is a trapped body of water and doesn’t get near the circulation that your pool gets. Its a good idea especially during the spring and summer months to put your system into “spa only mode” without heating the water. This will allow ALL the water to get filtered and if you do this pretty regularly you will notice that the spa will look just as good as the pool.